I use this adapter: http://arcadeforge.net/UMSA/UMSA-Ultima ... r::57.html
It's converting 15Khz RGBHV to 15Khz RGBS Scart. (Then I use Scart -> BNC for Sony PVM).
I intentionally used it for my raspberry pi to output 240P (works perfect). But now I gave it a shot with my Sony PVM (we have the same white one).
All cores who have Sorgelig's Scanline Option's work with that adapter and have no double image. (You have to set it to : none , with effects its double image).
For example C16, Aquarius, and so on is working for me with crystal clear image ....
The one's without scanline option's in the MISTer GUI (Apple II, Archie...) have a split image L/R with a black border in the middle.
So I think this adapter is good for better compatibility. Just for anyones confirmation.
Two beer or not two beer? - Shakesbeer.